Danger is an attention getting warning usallly followed by additional comments. In this case the top sign is for a “Pinch Point” which is a common type of transition connection in various machinery and equipment.
The bottom Danger sign warning to “Not Climb, Sit, Walk or Ride On Conveyor” was ignored by a worker who decided to climb onto the conveyor and consequently when the conveyor accidentally started to move he suffered various bodily injuries.